Microelectronic devices are generally fabricated from various microelectronic components, including, but not limited to, at least one microelectronic die (such as a microprocessor, a chipset, a graphics device, a wireless device, a memory device, an application specific integrated circuit, or the like), at least one passive component (such as resistors, capacitors, inductors and the like), and at least one microelectronic substrate (such as interposers, motherboards, and the like) for mounting the components. The various microelectronic components may be electrically interconnected to one another through solder interconnects extending between interconnection pads on one microelectronic component to interconnection pads on another microelectronic component.
The microelectronic industry is continually striving to produce ever faster and smaller microelectronic devices for use in various electronic products, including, but not limited to portable products, such as portable computers, digital cameras, electronic tablets, cellular phones, and the like. As the size of the microelectronic components, such as microelectronic devices and microelectronic substrates, are reduced, the current densities of the microelectronic components increases, as will be understood to those skilled in the art. As these current densities increase, surface finishes, which are disposed between interconnection pads and the solder interconnects, must not only form a ductile interconnection or “joint” between interconnection pads and the solder interconnects, but also have sufficiently strong electro-migration resistance to meet maximum current (Imax) demands of the smaller microelectronic components. Therefore, there is a need to develop surface finishes and methods of fabrication thereof that can provide a desired maximum current (Imax) while maintaining a ductile joint between interconnection pads and the solder interconnects.